Storage apparatus and load distribution method

• US 8,161,490 B2
• Filed: 01/04/2008
• Issued: 04/17/2012
• Est. Priority Date: 01/25/2007
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Watanabe, Koji, Sugimoto, Sadahiro
• Primary Examiner(s): Puente, Emerson
• Assistant Examiner(s): PATEL, HIREN P
• Application Number:
  US12/003,994
• Publication Number:
  US 20080184255A1
• Time in Patent Office: 1,565 Days
• Field of Search: None
• US Class Current: 718/105
• CPC Class Codes: G06F 2209/5022 Workload threshold
• CPC Class Codes: G06F 9/505 considering the load

Abstract

A storage apparatus having plural control processors that interpret and process requests sent from a host computer includes a distribution judgment unit for judging, after a control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from the control processor that received the request to another control processor, and a control processor selection unit for selecting an allocation target control processor if the distribution judgment unit judges to allocate the processing to another control processor.

Claims

1. A storage apparatus having plural control processors that interpret and process a request sent from a host computer, the storage apparatus comprising:

each of the control processors comprising;

a respective cycle processing unit for calculating average response time for the processing in the respective control processor during a prescribed time cycle;

a distribution judgment unit for judging, after a control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from that control processor to any other control processor; and

a control processor selection unit configured for selecting an allocation target control processor if the distribution judgment unit decides to allocate the processing to another control processor,

wherein the control processor selection unit of a first control processor of the plural control processors is configured to allocate, in the case in which the first control processor receives the request from the host computer and the distribution judgment unit of the first control processor judges to allocate the processing relevant to the request to another control processor, the processing relevant to the request to the another of the control processors based at least in part on the average response time of the first control processor and on the average response time of the another control processor,

wherein the cycle processing unit also is configured to determine a total number of requests received by the control processor and a number of allocations of processing relevant to the requests to any other of the control processors during a prescribed time cycle,

wherein the distribution judgment unit is configured to judge whether or not to allocate the processing relevant to the request to another control processor based on the total number of requests received by the control processor and the number of allocations of processing relevant to the requests to any other of the control processors during the prescribed time cycle, and

wherein the distribution judgment unit of the first control processor is configured to prohibit allocation of the processing to a second one of the control processors if the average response time for the processing in the second control processor exceeds a first threshold, and makes the second control processor resume accepting allocation from the first control processor if the average response time for the processing in the first control processor exceeds a second threshold.

2. The storage apparatus according to claim 1, wherein the distribution judgment unit decides a total number of allocations of the processing relevant to the request to another control processor based on the average response time for the processing in the control processor that received the request during a prescribed time cycle.

3. The storage apparatus according to claim 2, wherein the distribution judgment unit calculates a number of allocations of the processing relevant to each type of request made to any other of the control processors based on a number of received requests of each type and the total number of allocations of the requests to any other of the control processors.

4. The storage apparatus according to claim 1, wherein the control processor selection unit is configured to select the allocation target control processor from among the control processors other than the control processor that received the request, in the order of shorter average response time for the processing.

5. The storage apparatus according to claim 4, wherein the control processor selection unit is configured not to select again any control processor already selected once before until all control processors that can be allocation targets have been selected.

6. A load distribution method for a storage apparatus having plural control processors that interpret and process a request sent from a host computer, the method comprising:

a first step of calculating an average response time for the processing in the respective control processor during a prescribed time cycle;

a second step of judging, after a first control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from the first control processor that received the request to another control processor; and

a third step of selecting an allocation target control processor if the processing allocation is decided upon in the second step;

wherein the selecting step comprises, in the case in which the judging step judges to allocate the processing relevant to the request to another control processor, selecting the another of the control processors for the processing relevant to the request, based at least in part on the average response time of the first control processor and on the average response time of the another control processor,

wherein in the second step, whether or not to allocate the processing relevant to the request to any other of the control processors is determined based on a total number of requests received by the first control processor and a number of allocations of the processing relevant to the requests to any other of the control processors during the prescribed time cycle, and

wherein in the second step, allocation of the processing to a second one of the control processors is prohibited if the average response time for the processing in the second control processor exceeds a first threshold, and acceptance of allocation of the processing to the second control processor is resumed if the average response time for the processing in the first control processor exceeds a second threshold.

7. The load distribution method according to claim 6, wherein in the second step, the total number of allocations of the processing relevant to the requests to another of the control processors is determined based on average response time for the processing in the first control processor that received the request during the prescribed time cycle.

8. The load distribution method according to claim 7, wherein in the second step, the number of allocations of the processing relevant to each type of request to any other of the control processors is calculated based on a number of received requests of each type and a total number of allocations of the requests to another control processor.

9. The load distribution according to claim 6, wherein in the third step, the allocation target control processor is selected from among the control processors other than the control processor that received the request, in the order of shorter average response time for the processing.

10. The load distribution method according to claim 9, wherein in the third step, any control processor already selected once before is not selected again until all control processors that can be allocation targets have been selected.